Sequencing showed that all omicron variant strains were the subvariant BA.1, inclusive of sublineages. In all panels, shaded areas indicate 95% confidence intervals. Panels B through E show Kaplan–Meier survival curves for the time from an initial positive PCR assay to a negative PCR assay, according to viral variant (Panel B) and vaccination status (Panel D), and the time from an initial positive PCR assay to a negative viral culture, according to viral variant (Panel C) and vaccination status (Panel E). The median viral load at each time point for each variant is also shown. Each circle or triangle represents a sample obtained on the specified day. Viral loads from nasal-swab samples obtained from individual participants are shown. Panel A shows viral-load decay from the time of the first positive polymerase-chain-reaction (PCR) assay. Viral Decay and Time to Negative Viral Culture. This study was approved by the institutional review board and the institutional biosafety committee at Mass General Brigham, and informed consent was obtained from all the participants. Participants who received Covid-19–specific therapies were excluded all but 1 participant had symptomatic infection. 4 From July 2021 through January 2022, we enrolled 66 participants, including 32 with samples that were sequenced and identified as the B.1.617.2 (delta) variant and 34 with samples that were sequenced and identified as the omicron subvariant BA.1, inclusive of sublineages. We used longitudinal sampling of nasal swabs for determination of viral load, sequencing, and viral culture in outpatients with newly diagnosed coronavirus disease 2019 (Covid-19). 3 However, the viral decay kinetics of the omicron variant and the duration of shedding of culturable virus have not been well characterized. 1,2 Recently, the Centers for Disease Control and Prevention recommended shortening the strict isolation period for infected persons in non–health care settings from 10 days to 5 days after symptom onset or after the initial positive test, followed by 5 days of masking. The B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a shorter incubation period and a higher transmission rate than previous variants. The most trusted, influential source of new medical knowledge and clinical best practices in the world. Information and tools for librarians about site license offerings. Valuable tools for building a rewarding career in health care. The authorized source of trusted medical research and education for the Chinese-language medical community. The most advanced way to teach, practice, and assess clinical reasoning skills. Information, resources, and support needed to approach rotations - and life as a resident. The most effective and engaging way for clinicians to learn, improve their practice, and prepare for board exams. NEW! Peer-reviewed journal featuring in-depth articles to accelerate the transformation of health care delivery.Ĭoncise summaries and expert physician commentary that busy clinicians need to enhance patient care. NEW! A digital journal for innovative original research and fresh, bold ideas in clinical trial design and clinical decision-making.
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